U.S. patent number 5,849,090 [Application Number 08/622,844] was granted by the patent office on 1998-12-15 for granular resistant starch and method of making.
This patent grant is currently assigned to Opta Food Ingredients, Inc.. Invention is credited to Akiva Gross, Stephen G. Haralampu.
United States Patent |
5,849,090 |
Haralampu , et al. |
December 15, 1998 |
Granular resistant starch and method of making
Abstract
A method of producing a granular resistant starch comprising the
steps of heating a granular native starch to swell but not rupture
the starch granules, debranching the starch, treating the starch to
retrograde the amylose therein, optionally annealing the starch and
optionally drying the product to a powder is described. Granular
resistant starch produced by this method and food formulations
containing the granular resistant starch are also described.
Inventors: |
Haralampu; Stephen G.
(Plymouth, MA), Gross; Akiva (Newton, MA) |
Assignee: |
Opta Food Ingredients, Inc.
(Bedford, MA)
|
Family
ID: |
24495718 |
Appl.
No.: |
08/622,844 |
Filed: |
March 27, 1996 |
Current U.S.
Class: |
127/65; 127/32;
127/71; 426/661; 127/69; 127/67 |
Current CPC
Class: |
A23L
27/60 (20160801); C08B 30/12 (20130101); A23L
29/262 (20160801); A23C 9/137 (20130101); C12P
19/14 (20130101); A23L 29/212 (20160801); A23L
29/35 (20160801) |
Current International
Class: |
A23L
1/09 (20060101); A23L 1/0534 (20060101); A23C
9/13 (20060101); A23C 9/137 (20060101); A23L
1/24 (20060101); A23L 1/0522 (20060101); A23L
1/052 (20060101); C12P 19/00 (20060101); C12P
19/14 (20060101); C08B 30/12 (20060101); C08B
30/00 (20060101); C08B 030/00 (); C08B 030/12 ();
A23L 001/05 () |
Field of
Search: |
;127/65,67,69,71,32
;426/661 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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564893A1 |
|
Oct 1993 |
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EP |
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616779A1 |
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Sep 1994 |
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EP |
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688872A1 |
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Dec 1995 |
|
EP |
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747397A2 |
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Dec 1996 |
|
EP |
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91/07106 |
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May 1991 |
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WO |
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92/21703 |
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Dec 1992 |
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WO |
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94/14342 |
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Jul 1994 |
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WO |
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95/04082 |
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Feb 1995 |
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WO |
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Other References
Jane and Robyt, "Structure Studies of Amylose-V Complexes and
Retrograded Amylose by Action of Alpha Amylases, and a New Method
for Preparing Amylodextrins", Carbohydrate Research 132:105-118.
.
Englyst and Cummings, "Digestion of the Polysaccharides of Some
Cereal Foods in the Human Small Intestine", Am. J. Clin. Nutr.
42:778-787 (Nov. 1985). .
Annison and Topping "Nutritional Role of Resistant Starch: Chemical
Structure vs Physiological Function" Annu. Rev. Nutr. 14:297-320
(1994) month n/a. .
Garcia et al., Starch 49:171-179 (1997) [(Exhibit A of an amdt.
filed Jul. 16, 1997)]..
|
Primary Examiner: Jones; Deborah
Assistant Examiner: Hailey; Patricia L.
Attorney, Agent or Firm: Hamilton, Brook, Smith &
Reynolds, P.C.
Claims
We claim:
1. A method for producing granular resistant starch, comprising the
steps of:
a) heating an aqueous slurry of native starch under conditions
appropriate for swelling of the native starch granules therein
without causing rupture of said native starch granules;
b) debranching the starch product of step (a); and
c) causing the debranched starch product of step (b) to
retrograde,
thereby producing granular resistant starch.
2. A method according to claim 1, wherein step (b) is carried out
using a debranching enzyme.
3. A method according to claim 2, wherein the debranching enzyme is
pullulanase.
4. A method according to claim 1, wherein the native starch is a
high amylose starch.
5. A method according to claim 4, wherein the native starch is
derived from corn, potato, wheat, rice, barley, tapioca, cassava,
arrow-root, sago and oat starches.
6. A method according to claim 1, further comprising annealing the
starch after step (b).
7. A method according to claim 6, further comprising drying the
annealed product.
8. A method according to claim 1, further comprising drying the
product of step (c).
9. Granular resistant starch produced by the method of claim 1.
10. A food or beverage formulation comprising the granular
resistant starch of claim 9.
11. A food or beverage formulation according to claim 10, wherein
the food or beverage formulation is selected from the group
consisting of cookies, breads, cakes, pies, noodles, fudge,
brownies, low-fat margarine, snack dips, sour cream, mayonnaise,
cream cheese, spreads, yogurt, milkshakes, ice cream, frozen
desserts, crackers, graham crackers, pretzels, extruded cereals and
extruded snacks.
12. A food or beverage formulation according to claim 10, wherein
the granular resistant starch is present at from about 1% to about
15%.
13. A food or beverage formulation which is a source of
slow-released glucose comprising the granular resistant starch of
claim 9.
14. A method of producing granular resistant starch, comprising the
steps of:
a) heating an aqueous slurry of native high amylose starch to a
temperature of from about 90.degree. C. to about 120.degree.
C.;
b) enzymatically debranching the starch product of step (a);
and
c) heating the debranched starch product of step (b) to a
temperature of from about 40.degree. C. to about 100.degree. C. and
maintaining the temperature for about 2 hours,
thereby producing granular resistant starch.
15. A method according to claim 14, further comprising:
d) altering the temperature of the product of step (c) to achieve a
temperature of from about 40.degree. C. to about 60.degree. C. over
the course of about 4 hours,
thereby producing granular resistant starch.
16. A method according to claim 15, wherein steps (c) and (d) are
repeated sequentially at least once.
17. Aqueous granular resistant starch produced by a process which
causes native starch granules to swell but not rupture and wherein
the starch has an average viscosity lower than the average
viscosity of resistant starch produced by a process in which the
starch granules are ruptured.
18. A food or beverage formulation comprising the aqueous granular
resistant starch of claim 17.
19. A food or beverage formulation according to claim 18, wherein
the food or beverage formulation is selected from the group
consisting of cookies, breads, cakes, pies, noodles, fudge,
brownies, low-fat margarine, snack dips, sour cream, mayonnaise,
cream cheese, spreads, yogurt, milkshakes, ice cream, frozen
desserts, crackers, graham crackers, pretzels, extruded cereals and
extruded snacks.
20. A food or beverage formulation which is a source of
slow-released glucose comprising the aqueous granular resistant
starch of claim 17.
21. A method for producing granular resistant starch, comprising
the steps of:
a) heating an aqueous slurry of native starch having a moisture
content of from about 100% to about 600% starch weight under
conditions appropriate for swelling of the native starch granules
therein without causing rupture of said native starch granules;
b) debranching the starch product of step (a); and
c) maintaining the debranched starch product of step (b) at an
appropriate temperature and for an appropriate time to cause the
starch product to retrograde,
thereby producing granular resistant starch.
22. Granular resistant starch produced by the method of claim
21.
23. A method according to claim 21, wherein the moisture content is
from about 270% to about 500% starch weight.
24. Aqueous granular resistant starch having a moisture content of
from about 100% to about 600% starch weight and having an average
viscosity lower than the average viscosity of resistant starch
produced by a process in which the starch granules are ruptured.
Description
BACKGROUND OF THE INVENTION
Resistant starch is the portion of starch which, due to physical
constraints, is poorly hydrolyzed by amylases. Some of the
conditions which limit enzymatic hydrolysis are physical entrapment
in a non-digestible matrix, crystallinity due to structure in
ungelatinized starch granules which may be destroyed at relatively
low temperatures and crystallinity due to retrogradation which is
considerably more stable. The resistance of starches has been
investigated by a number of researchers (e.g., Jane and Robyt,
Carbohydrate Research 132:105-118 (1984); Englyst and Cummings, Am.
J. Clin. Nutr. 42:778-787 (1985); and Annison and Topping, Annu.
Rev. Nutr. 14:297-320 (1994)).
One feature of resistant starch is that it interferes with the
traditional measurement of total dietary fiber by the Prosky method
(Englyst et al., Analyst 107:307-318 (1982)), which has generated
considerable controversy. Since the classical definition of fiber
is non-starch polysaccharide, resistant starch should not be
considered fiber by the classical definition. However, nutritional
studies show that resistant starch possesses some of the
physiological benefits of fiber, and should be properly considered
as a fiber. Some benefits cited include increased fecal bulk,
lowered fecal pH, increased excretion of butyrate and acetate
(Phillips et al., Am. J. Clin. Nutr. 62:121-130 (1995)), increased
ilial crypt cell production rate (Gee et al., J. Nutr. 121:44-49
(1991)), and decreased serum triacylglycerol concentration
(DeDeckere et al., Br. J. Nutr. 73:287-298 (1995)). These benefits
are primarily seen in soluble dietary fibers.
In addition to utility as a fiber constituent, the slow hydrolysis
of resistant starch makes it useful for the slow release of
glucose, which can be especially useful in controlling glycemic
plasma responses (Raben et al., Am. J. Clin. Nutr. 60:544-511
(1994)). U.S. Pat. No. 5,470,839 (Laughlin et al.) teaches the use
of raw high amylose starch as a source of resistant starch useful
for foods for diabetics.
Methods for producing resistant starch products disclosed in U.S.
Pat. Nos. 5,051,271 (Iyengar et al.) and 5,409,542 (Henley et al.)
utilize the steps of fully hydrating and cooking a starch,
preferably a high amylose hybrid, optionally enzymatically
debranching the amylopectin therein, and incubating the mixture
under conditions to retrograde the amylose to yield resistant
starch. One disadvantage of these methods is that full hydration
and cooking of the starch produces mixtures with very high
viscosities during the retrogradation. High viscosities are managed
by running at low concentration, which is inefficient and results
in excessive drying costs when producing a powdered ingredient.
SUMMARY OF THE INVENTION
The present invention pertains to a method of making granular
resistant starch comprising heating a granular native starch to
cause the native starch granules to swell but not rupture,
debranching the swollen native starch, treating the debranched,
granular starch to retrograde the amylose, and optionally annealing
the starch, thereby producing granular resistant starch. The
invention also relates to granular resistant starch produced by the
process described herein, and food formulations comprising the
granular resistant starch.
In one embodiment of the invention, an aqueous slurry of a granular
native starch is heated (e.g., with a batch tank heater or heating
plate) to a temperature sufficient to swell the native starch
granules without disrupting the starch granules. The swelled
granular native starch is then treated with a debranching enzyme
(e.g., pullulanase) under conditions appropriate to substantially
or totally debranch the amylopectin present in the starch. The
debranched granular starch is treated under thermal conditions
sufficient to retrograde the amylose. The product of the described
process can be cooled to form an aqueous granular resistant starch
slurry having a lower viscosity than resistant starches produced by
traditional processes. The aqueous slurry can optionally be dried
(e.g., by spray drying) to a powder. The granular resistant starch
will have a total dietary fiber (TDF) content of from about 20% to
about 50% by weight.
In another embodiment of the invention, the retrograded starch can
optionally be annealed. Annealing promotes perfection of order in
the starch structures and enhances the yield of thermally stable
retrograded starch as measured by differential scanning calorimetry
(DSC) peak enthalpy, resistant starch or percent TDF. Annealing can
be accomplished by oscillating the temperature between a
temperature just below the melting point of the starch and a
temperature just above the glass transition temperature.
Alternatively, the temperature can be maintained just below the
melting point of the starch for a time sufficient to anneal the
starch. The annealing step can be carried out concurrently with or
after the retrogradation step. In a particular embodiment, the
annealing cycle is carried out more than once. The product of the
described annealing process can be cooled to form an aqueous
granular resistant starch slurry having a lower viscosity than
resistant starches produced by prior art methods. The aqueous
slurry can optionally be dried (e.g., by spray drying) to a
powder.
The granular resistant starch can also be optionally co-processed
with hydrocolloids, polymers, gums, modified starches and
combinations thereof, which additional ingredients can be added to
change the functional properties of the granular resistant starch.
For example, the granular resistant starch can be co-processed with
dispersion aids, such as maltodextrin, or hydrocolloids, which can
assist in altering the functional properties of the composition
such as viscosity building and water binding.
The granular resistant starch produced by the described process is
characterized by TDF values in the range of from about 20% to about
50% by weight. The aqueous granular resistant starch slurry will
have a lower viscosity than resistant starch slurries produced by
traditional processes of the prior art. In the present invention,
it is preferable to form thermally stable retrograded amylose
(thermally stable resistant starch) with a DSC peak above about
125.degree. C., as such starch is sufficiently thermally stable to
survive most cooking processes.
The granular resistant starch produced by the methods described
herein is useful in a variety of food and beverage applications.
Foods and beverages which can be formulated with the granular
resistant starch of the present invention include cookies, breads,
cakes, pies, noodles, fudge, brownies, low-fat margarine, snack
dips, sour cream, mayonnaise, cream cheese and other spreads,
yogurt, milkshakes, ice cream and frozen desserts. The granular
resistant starch can also be included in snack item formulations
such as crackers, graham crackers, pretzels and similar products,
as well as in extruded foods such as extruded snacks and
cereals.
By maintaining the starch granule integrity, the method of making a
granular resistant starch composition described herein has the
advantage of producing a composition with a significant percent of
total dietary fiber while avoiding the extremely high viscosities
encountered during retrogradation in traditional resistant starch
processes. The high viscosities produced during starch
retrogradation in prior methods requires that the process be run at
low concentrations, which is inefficient and results in excessive
drying costs when producing a powdered composition. One advantage
of the present invention is that thermally stable granular
resistant starch can be efficiently produced with reduced process
complexity due to the increased concentrations which can be
utilized.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a method of making granular resistant
starch by heating a granular native starch under conditions
sufficient to swell the starch granules, subsequently debranching
the amylopectin present in the starch, and treating the granular
debranched starch under conditions sufficient to retrograde the
amylose and, optionally, anneal the starch. The granular resistant
starch produced by the described process can be utilized in the
form of an aqueous dispersion or can be dried to a powder. The
powder can optionally be redispersed in an aqueous medium with
medium shear.
Any native or pregelatinized starch can be used as the starting
material of the present invention as long as the starch granules
therein are intact. Particularly preferred starches are high
amylose starches, most preferably starches containing at least 30%
amylose, when measured by iodine binding (Schoch, T. J., Methods in
Carbohydrate Chemistry 4:157-160 (1964)). Suitable starches include
corn, potato, wheat, rice, barley, tapioca, cassava, arrow-root,
sago and oat starches. For example, a hybrid of corn starch, such
as starch from the ae7 hybrid of corn, available under the trade
names AMYLOMAIZE VII.RTM. (American Maize Products Company,
Hammond, Ind.) and HYLON VII.RTM. (National Starch and Chemical
Company, Bridgewater, N.J.), is a particularly suitable starch.
This starch will assay to less than about 20% TDF (total dietary
fiber) and when analyzed by differential scanning calorimetry (DSC)
exhibits thermal activity peak (gelatinization) from about
55.degree. C. to 130.degree. C. with a peak at about 95.degree. C.
and total peak enthalpy of about 24 J/g. The product of this
invention assays from about 20% to about 50% TDF by weight and is
shown to be more thermally stable when analyzed by DSC since it
exhibits thermal activity from about 90.degree. C. to 150.degree.
C. with a peak at about 125.degree. C. Thus, since the thermal
activity is higher than normal cooking temperatures, resistance is
preserved in most food processes.
The granular native starch is combined with an aqueous medium such
as water or a buffer to produce a slurry; the aqueous medium can
also be a mixed organic solvent (such as a mixture of water and
alcohol), depending upon the desired end product. Generally, food
grade aqueous media should be used if the ultimate use is a food or
beverage product. The dispersion or slurry generally contains from
about 1% to about 50% (w/w) of starch. The slurry is then heated
under conditions sufficient to swell the native starch granules
present in the slurry without rupturing the starch granules. That
is, under heating conditions appropriate for this step of the
invention, the granular structure of the starch is not disrupted,
and the starch granules, although swollen, remain intact.
Swelling the starch granule hydrates the starch molecules,
presumably making them accessible for subsequent debranching and
making them sufficiently mobile to retrograde into thermally stable
resistant starch with a DSC peak at about 125.degree. C. By
maintaining some granule integrity, however, the extremely high
viscosities encountered during retrogradation in traditional
resistant starch processes are significantly lowered.
Generally, temperatures considered appropriate for the present
invention range from about 60.degree. C. to about 120.degree. C.,
with from about 70.degree. C. to about 100.degree. C. being
particularly preferred. For example, in the case of AMYLOMAIZE
VII.RTM. (73% amylose corn starch), temperatures sufficient to
swell the granules without disrupting them are from about
60.degree. C. to about 100.degree. C., and preferably from about
75.degree. C. to about 90.degree. C. The type of heating equipment
is not critical, and heating may be accomplished by a jacketed
reactor, heat exchanger, extruder or direct steam injection.
Generally, the time required to sufficiently swell the starch
granules will be less than about 2 hours, with less than about 1
hour being preferred, depending upon the starch used.
In some cases, a small amount of amylose leaches from the starch
granules during the swelling process, building viscosity during the
retrogradation part of the process. This phenomenon can be
controlled by regulating the time and temperature conditions used
to swell the starch granules and depends upon the type of starch
used as a starting material. For instance, the time and/or
temperature of the swelling step can be reduced to minimize amylose
leakage.
Since the retrogradation of amylose is retarded by the presence of
amylopectin in the starch, once the starch granules have been
sufficiently swollen, the starch is treated to release short chain
amylose. Generally, release of the short chain amylose from the
starch will be carried out by enzymatically debranching the starch,
e.g., the starch can be debranched with .alpha.-1,6-specific
glycosidic enzymes which are capable of cleaving
.alpha.-1,6-D-glucosidic linkages. For instance, the starch can be
treated with an isoamylase or with a pullulanase at a temperature
and pH and for a time sufficient to allow the enzyme to release the
short chain amylose; often, appropriate reaction conditions will be
suggested by the manufacturer. A suitable pullulanase can be
purchased commercially under the trade name PROMOZYME.RTM. 200L
(Novo Nordisk Biochem North America, Inc., Franklinton, N.C.).
Generally, appropriate temperatures will range from about
25.degree. C. to about 100.degree. C., with from about 55.degree.
C. to about 65.degree. C. being preferred, for a time of from about
half an hour to about 30 hours, with from about half an hour to
about 4 hours being particularly preferred, depending on the enzyme
utilized, the enzyme concentration, and the starting material.
Furthermore, the pH of the solution as is optimal for enzyme
activity will be from about 3 to about 7.5. In a particularly
preferred method, the granular starch is treated with pullulanase
at 60.degree. C. at pH 5 for about 4 hours. The optimum conditions
for the enzymatic reaction will vary, with changes in parameters
such as starch and enzyme concentrations, pH, temperature and other
factors readily determinable by the skilled artisan.
Alternatively, the starch can be randomly hydrolyzed and debranched
by use of an appropriate acid, such as a mineral acid or organic
acid; generally acid hydrolysis will take place at a pH of less
that about 4 and at a temperature greater than about 60.degree. C.
but less than the gelatinization temperature of the particular
starch used, depending upon the acid used. The conditions for acid
hydrolysis should be such that inappropriate side reactions are
minimized and the starch granules remain intact. Short chain
amylose can also be generated by treating the starch with an alpha
amylase, alone or in combination with pullulanase.
Without wishing to be bound by theory, debranching presumably
enhances the described process by increasing the relative
concentration of straight chain molecules, or by removing the
inhibitory effects of amylopectin on the retrogradation of
amylose.
After the starch is substantially or totally debranched, the
debranched granular starch is treated under conditions sufficient
to retrograde the amylose, thereby forming crystalline regions in
the starch molecule interspersed with amorphous regions.
Preferably, the resulting granular resistant starch has a TDF value
of from about 20% to about 50%.
As defined herein, thermally stable resistant starch is a resistant
starch which exhibits most of its thermal activity above
100.degree. C., and is generally derived from retrograded amylose.
In the present invention, it is preferable to form thermally stable
retrograded amylose (thermally stable resistant starch) with DSC
peak above about 125.degree. C. Generally, retrogradation is
accomplished by incubating an aqueous mixture of the debranched
granular starch at temperatures ranging from about 1.degree. C. to
about 120.degree. C. for sufficient time to allow retrogradation to
proceed maximally; appropriate times range from about 4 hours to
about 100 hours, with from about 4 hours to about 24 hours
particularly preferred, depending upon the starch and temperature
conditions. To minimize viscosity build-up, elevated temperatures
during retrogradation are preferred in the range of from about
60.degree. C. to about 120.degree. C., and from about 70.degree. C.
to about 100.degree. C. is most preferred as being the temperature
range which both allows retrogradation to proceed at a suitable
rate, while keeping process viscosities manageable. Temperatures
within the disclosed ranges also serve to inactivate the remaining
debranching enzyme.
Annealing may also be optionally introduced into the process.
Annealing promotes perfection of order in the starch structures,
and enhances the yield of retrograded starch as measured by DSC
peak enthalpy, resistant starch or TDF. Annealing may be carried
out after the granular starch is debranched; that is, annealing can
take place concurrently with or after the retrogradation step. In
an annealing process, temperatures are oscillated in the range of
1.degree. C. to 120.degree. C., and preferably in the range of
50.degree. C. to 90.degree. C. Relatively short times at 90.degree.
C., on the order of 1 hour, with slow cooling, on the order of
about 4 hours, to about 50.degree. C., with a subsequent hold at
about 50.degree. C. for about 4 hours comprise a single cycle of
the preferred annealing process. Preferably, the annealing cycle is
carried out more than once, with two to four annealing cycles being
particularly preferred. Alternatively, the granular resistant
starch product can be maintained at a temperature slightly below
the melting point of the starch for a time of from about 4 hours to
about 100 hours.
The product which results if the annealing step is performed is
similar to the product obtained if this step is not carried out,
except that the product of the annealing step may have increased
TDF values and a more sharply defined peak measured by DSC.
Regardless of whether the annealing step is carried out or not, the
aqueous granular resistant starch can be used in its aqueous form
or can be dried to a powder by a number of art-recognized methods,
including spray drying, belt drying, freeze drying, drum drying or
flash drying. The powder can be stored at room temperature, and can
be redispersed in water or another aqueous medium, preferably an
aqueous medium which is appropriate for use in food and beverage
formulations, under conditions of medium shear. The granular
resistant starch of the present invention can be used in food
formulations in either form (e.g., aqueous or powder), depending
upon the food formulation.
The granular resistant starch can also be co-processed with
hydrocolloids, gums, polymers, modified starches and combinations
thereof to change the functional properties of the product. For
example, xanthan, alginate, carrageenan, carboxymethyl cellulose,
methyl cellulose, guar gum, gum arabic, locust bean gum and
combinations thereof can be added to the starch at any time during
the preparation process, provided that the additional ingredient(s)
does not prevent the swelling of the starch granule, the
debranching of the amylopectin or the retrogradation of the
amylose. That is, these additional ingredients can be heated along
with the starting native starch, added prior to or after the
debranching step, added to the aqueous slurry of granular resistant
starch or dry blended with the powdered composition after drying.
Preferably the hydrocolloid, gum, modified starch or polymer is
added to the aqueous granular starch slurry prior just prior to
drying.
The granular resistant starch produced by the present invention
assays as dietary fiber by the Prosky method. The granular
resistant starch has a microcrystalline structure and a wide range
of water-holding capacities and digestibility. It can be used as a
dietary fiber supplement, as a replacement or substitute for sugar
and flour in a variety of baked goods, as a fat extender in reduced
fat, low-fat and fat free formulations, as a tabletting aid and as
an inhibitor of excessive ice crystal formation in frozen
products.
The granular resistant starch of the present invention is
particularly useful in formulating foods and beverages containing
reduced amounts of sugar, flour or fat. Generally, the granular
resistant starch will be present in food formulation in amounts
ranging from about 1% to about 15%. Foods formulated with the
composition of the present invention in place of sugar, flour
and/or fat have a lower calorie content, a higher fiber content
and/or a lower fat content. Foods and beverages which can be
formulated with the granular resistant starch of the present
invention include cookies, breads, cakes, pies, noodles, fudge,
brownies, low-fat margarine, snack dips, sour cream, mayonnaise,
cream cheese and other spreads, yogurt, milkshakes, ice cream and
frozen desserts. The granular resistant starch can also be included
in snack item formulations such as crackers, graham crackers,
pretzels and similar products, as well as extruded foods such as
extruded cereals and snacks. The granular resistant starch of the
present invention is also suitable for inclusion in nutritional and
dietary drinks, as well as in foods for diabetics which are useful
for the slow release of glucose. The granular resistant starch of
the present invention can be used in sugar-free foods as well; the
amount of sugar, flour or fat in a given formulation which can be
replaced with the granular resistant starch will depend in part on
the formulation, the desired properties of the food and the amount
of calorie and/or fat reduction or fiber content desired. The
granular resistant starch of the present invention can also be
added as an extender to a formulation without reducing any of the
other ingredients. The extended product has a lower calorie or fat
content per volume compared with the unextended product.
The following Examples are offered for the purpose of illustrating
the present invention and are not to be construed to limit the
scope of this invention. The teachings of all references cited
herein are hereby incorporated herein by reference.
EXAMPLES
Example 1
A slurry of 40 grams HYLON VII.RTM. (National Starch and Chemical
Company) in 160 ml was prepared and heated to 90.degree. C. on a
heating plate, and held covered at 95.degree. C. for 2 hours in an
oven. The mixture was cooled to 57.degree. C. and 0.8 ml of
PROMOZYME 200L.RTM. (Novo Industri, A/S) was added to debranch the
starch. Debranching and retrogradation continued at 57.degree. C.
for about 3 days.
After debranching, the starch mixture was heated to 90.degree. C.
in an incubating oven for about 140 minutes to inactivate the
enzyme and anneal the retrograded starch.
The starch mixture was freeze dried. The resultant powder was
analyzed for percent total dietary fiber (TDF) using the Prosky
Method (AACC Method 32-07), and found to be 29.0% TDF. DSC analysis
(Perkin-Elmer, DSC-7) confirmed a retrograded starch peak from
90.degree. C. to 130.degree. C. the effectiveness of the
debranching enzyme was confirmed by high performance size-exclusion
chromatography (HPSEC) analysis showing a molecular weight (weight
average) of 231,000 daltons, in contrast to the starting HYLON
VII.RTM. at 1,150,000 daltons.
Example 2
A 25% slurry of high amylose corn starch was prepared by blending
35 kg of HYLON VII.RTM. and 94.6 liters of water in a
scraped-surface, hemispherical bottom, jacketed kettle. The slurry
was heated to boiling and maintained at 95.degree. C. to
100.degree. C. for about 1 hour. At this point there was a slight
thickening of the starch slurry, indicative of the granules
swelling. Next, the slurry was cooled to 57.degree. C. and pH
adjusted to 4.9 with dilute phosphoric acid.
Approximately 76 liters of the cooled slurry was debranched with a
pullulanase. The enzyme was added at 5% on a starch basis, or 977
ml per 72.3 kg of slurry. The slurry was maintained at 57.degree.
C. by tempered water on the vessel jacket and agitated overnight.
During this period, the enzyme debranched the amylopectin and the
starch retrograded to form the thermally resistant form as
quantified by a DSC peak at approximately 125.degree. C.
After the overnight incubation, the slurry was heated to 90.degree.
C. for a period of two hours to inactivate the enzyme and to anneal
the retrograded starch, as is quantified by better definition of
the high temperature DSC peak.
After the two hour annealing period, the starch was dried in a
spray dryer. To facilitate atomization, the slurry was diluted with
water, maintained at 90.degree. C. and sprayed with a 2-fluid
nozzle, using air as the second fluid. Dilution is presumed to be
unnecessary for commercial implementation should suitable drying
equipment be available.
The resultant powder was analyzed to be 32.6% TDF. DSC analysis
confirmed a retrograded starch peak from 99.degree. C. to
147.degree. C. The effectiveness of the debranching enzyme was
confirmed by HPSEC analysis showing a molecular weight (weight
average) of 292,000 daltons.
Example 3
A 15% high amylose starch slurry was prepared by blending 11 kg of
HYLON VII.RTM. (National Starch and Chemical Company) and 57 liters
of water in a scraped-surface, hemispherical bottom, jacketed
kettle. The slurry was heated to about 100.degree. C. over a period
of about 50 minutes, and immediately cooled to about 68.degree. C.
over a period of about 50 minutes. The pH was 5.0 and did not
require adjustment for the debranching enzyme. The debranching
enzyme (PROMOZYME 200L.RTM.) was added at 3% based on starch, or
340 ml. The enzyme reaction was allowed to proceed for 3 hours,
after which the temperature was raised to 90.degree. C., held for 1
hour, and then the temperature was cycled between about 88.degree.
C. and about 58.degree. C. to anneal the product. Each thermal
cycle consisted of a linear cool lasting 2.8 hours, followed by a
1-hour heating to 88.degree. C. and a 10-minute hold at 88.degree.
C. There were a total of four cycles.
The resulting batch was split into two portions. One portion of the
batch was spray dried, yielding a white flowable powder. The
product assayed as 28% TDF, and had a 20.mu. median particle size
as measured on a Microtrac.TM. (Leeds and Northrup Instruments,
North Wales, Pa.). The resistant starch was confirmed by a DSC peak
from 99.degree. C. to 146.degree. C.
The second portion of the batch was co-processed with the
hydrocolloid sodium carboxymethyl cellulose (CMC). A 9.5 kg portion
of slurry was assayed as 18.3% solid, or containing 1.7 kg of
granular resistant starch. The CMC was added on a 10% basis
relative to the starch as a 3% aqueous solution. The gum solution
was prepared by blending 172 g AQUALON TYPE 7MF.RTM. (Hercules
Corporation, Wilmington, Del.) and 5.8 liters of water and adding
this to the granular resistant starch slurry. This was spray dried,
yielding a white flowable powder. The product assayed as 34% TDF
and had a median particle size of 20.mu. as measured on a Microtrac
(Leeds and Northrup Instruments, North Wales, Pa.). The higher
fiber content reflects the soluble fiber contribution of the CMC.
The granular resistant starch was confirmed by a DSC peak from
83.degree. C. to 146.degree. C.
Example 4
A 15% high amylose starch slurry was prepared by blending 11 kg
HYLON VII.RTM. (National Starch and Chemical Company) and 57 liters
of water in a scraped-surface, hemispherical bottom, jacketed
kettle. The pH was 5.0 and did not require adjustment for the
debranching enzyme. The slurry was heated to about 100.degree. C.
over a period of about 40 minutes, and immediately cooled to about
59.degree. C. over a period of about 20 minutes. After heating, the
pH had dropped to 4.8. The debranching enzyme (PROMOZYME.RTM. 200L)
was added at 3% based on starch (dry weight basis) or 306 ml. The
enzyme reaction proceeded for 3 hours, after which the temperature
was raised to 90.degree. C., held for 1 hour, and then gradually
cooled to 55.degree. C. over a 4 hour period and held at 55.degree.
C. for an additional 12 hours. The retrograded starch slurry was
then spray dried. The granular resistant starch product assayed as
28.7% TDF. Thermally stable resistant starch was confirmed by a DSC
peak from about 95.degree. to 145.degree. C., with a minor peak at
107.degree. C. and a broad peak at 120.degree. C.
Example 5
The granular resistant starch of Example 4 was formulated into a
yogurt at a level of 1.1% TDF (a level sufficient for a "good
source of fiber" by current food regulations). For the 28.7% TDF
product of Example 4, this corresponds to a yogurt formulation
of:
______________________________________ Water 1684 g Non-fat dry
milk 240 g granular resistant starch 76 g
______________________________________
The dry ingredients were blended, split in two equal portions,
which were then dispersed in 300 ml water in each of two Waring
Blenders set on high. The mixtures were blended for 2 minutes. The
two portions were combined together and with the remaining water.
The mixture was then pasteurized by heating to 91.degree. C. in a
double boiler, and transferred to a thermos to stand for 30
minutes. The hot mixture was homogenized in an APV/Gaulin (Everett,
Mass.) homogenizer set for 2000 psi in the first stage and 500 psi
in the second. The mixture was then cooled to 43.degree. C. and
inoculated with 0.026% yogurt culture YC186 (Chr. Hansen,
Milwaukee, Wis.). The yogurt was incubated at 43.degree. C. for 6.5
hours before refrigeration at 4.degree. C.
An advisory panel viewed the yogurt as acceptable, with only minor
mouth-drying. A fiber assay indicated the yogurt to be 1.43% TDF,
1.18% insoluble fiber and 0.25% soluble fiber. This indicates that
the granular resistant starch is sufficiently thermally stable to
survive typical food processes like pasteurization and
homogenation.
Analytical Methods
DSC Thermal Analysis
Ten milligrams of powdered sample was weighed in a Perkin Elmer
high pressure capsule DSC pan. The sample was mixed with 50 .mu.l
deionized water and hermetically sealed in the DSC pan. The sample
was then analyzed (DSC 7, Perkin-Elmer, Norwalk, Conn.) from
20.degree. C. to 160.degree. C. at 10.degree. C./minute with a
sealed empty pan as a reference.
Molecular Weight Distributions
The molecular weight distributions of the debranched samples were
analyzed by high performance size-exclusion chromatography (HPSEC).
Two Polymer Laboratory (Amherst, Mass.) mixed bed B columns
(300.times.7.5 mm) were connected in series and the temperature of
the column maintained at 70.degree. C. The mobile phase was 5 mM
sodium nitrate in DMSO at a flow rate of 1 ml/minute. A Waters 400
refractive index detector (Waters Corporation, Milford, Mass.) was
used. The columns were calibrated using pullulan standards
(Hayashibara Biochemicals, Japan) with molecular weights ranging
from 5800 to 1.66.times.10.sup.4 daltons and maltose (molecular
weight 342 daltons). The molecular weights of the starch samples
were obtained using Perkin Elmer's Turbochrome 4 software and the
calibration curve for the standards. The starch samples (10 mg)
were completely issolved in 4 ml mobile phase by heating at
90.degree. C. in a water bath for 1 hour. A 200 .mu.l sample was
injected onto the columns.
Equivalents
Those skilled in the art will recognize, or be able to ascertain,
using no more than routine experimentation, many equivalents to the
specific embodiments of the invention described herein. Such
equivalents are intended to be encompassed by the following
claims:
* * * * *